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A Climate Change Resource for K-12 STEM Teachers

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A Climate Change Resource for K-12 STEM Teachers A Climate Change Resource for K-12 STEM Teachers Prepared by AAAS STEM Volunteers, www.stemvolunteers.org. Introduction The AAAS STEM Volunteer Program has prepared this resource on climate change for K-12 STEM teachers. We encourage educators to read, discuss, share, and use the information in their classrooms. Possible uses could include: constructing climate change problems, placing green school activities in the context of climate change, providing the information to IB and AP high school courses, or just adding to your own knowledge about this very important topic. In the document, we offer information to support the following: • The Earth’s atmosphere and oceans are warming. • The Earth’s climate and ecosystems are responding to this warming of the atmosphere and oceans. • What is the scientific understanding of these changes? • What does this scientific understanding predict for Earth’s future climate? • What do we do to address the consequences of climate change? • What actions can be taken to reduce the emissions of greenhouse gases? • What actions can be taken to protect from impacts? 2 The Earth’s atmosphere and oceans are warming. Earth’s land, ocean, and atmosphere temperatures have been steadily increasing since the Industrial Revolution. Satellite and surface measurements indicate that Earth’s land and ocean surface temperatures have increased by almost 2°F during that time.* Global annual average temperature has increased by more than 1.2°F (0.7°C) for the period 1986-2016 relative to 1901-1960. The red bars show temperatures that were above the 1901-1960 average, and blue bars indicate temperatures below the average. Source: https://science2017.globalchange.gov/chapter/executive-summary/ *As a point of comparison, the historical difference between an ice age and the earth temperature at year 1850 is about 4C° or 7°F. 3 There have been marked changes in temperature extremes across the contiguous United States. The number of high temperature records set in the past two decades far exceeds the number of low temperature records. (Very high confidence) Source: https://science2017.globalchange.gov/chapter/executive-summary/ 4 The Earth’s climate and ecosystems are responding to this warming of the atmosphere and oceans. 1. Glaciers around the world are receding. Credit: 1899 Olympic National Park archives. 2008: Jim Patterson, ONP Source: https://www.nps.gov/olym/learn/nature/glaciers.htm 5 2. Arctic sea ice is steadily receding. Source: https://science2017.globalchange.gov/chapter/executive-summary/ 6 3. Sea level is rising around the world. Source: https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level 7 4. There is extensive bleaching of corals, due primarily to increase of water temperature. A contributing factor is increased acidity, due to dissolved carbon dioxide. This graphic provides an overview on how coral becomes bleached. Source: NOAA’s Coral Reef Conversation Program, http://coralreef.noaa.gov/ 8 5a. There has been an increase in heavy precipitation. Credit: Figure adapted from article in Bulletin of the American Meteorological Society. See caption for details. Source: http://nca2014.globalchange.gov/highlights/report-findings/extreme-weather 9 5b. The intensity, frequency and duration of hurricanes have increased. There has been a substantial increase in most measures of Atlantic hurricane activity since the early 1980s, the period during which high quality satellite date are available. These include measures of intensity, frequency, and duration as well as the number of strongest (Category 4 and 5) storms. The recent increases in activity are linked, in part, to higher sea surface temperatures in the region that Atlantic hurricanes form in and move through. Credit: Photo courtesy of NOAA. Source: http://nca2014.globalchange.gov/highlights/report-findings/extreme-weather 10 6. There has been an Increase in heat waves. Heat waves are periods of abnormally hot weather, lasting days to weeks. The number has been increasing in recent years. This trend has continued in 2011 and 2012, with the number of intense heat waves being almost triple the long-term average. Recent heat waves in Texas (2011) and the Midwest (2012) set records for highest monthly average temperatures. Analyses show that climate change has generally increased the probability of heat waves. Prolonged (multi-monthly) extreme heat has been unprecedented since the start of reliable instrumental records in 1895. Earth’s 2015 surface temperatures were the warmest since modern record keeping began in 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA). Credit: Scientific Visualization Studio/Goddard Space Flight Center Source: https://www.nasa.gov/press-release/nasa-noaa-analyses-reveal-record-shattering-global-warm-temperatures-in-2015 11 7. Extreme and unusual temperature trends continue after 2016 which was a record year. Source: Global Climate Report – March 2017, https://www.ncdc.noaa.gov/sotc/global/201703 12 What is the scientific understanding of these changes? The changes in the environment and climate are due to increasing emissions of greenhouse gases, primarily carbon dioxide. The gases are called greenhouse gases because they trap heat in the atmosphere just like a greenhouse traps heat. But the heating mechanisms differ. For a conventional greenhouse, the heat transfer mechanisms are conduction and convection, while the mechanism for Earth is radiation. How does a greenhouse work? The sun’s radiation comes in through the glass roof of the greenhouse and heats the ground and vegetation which heat the air on contact. The hot air rises but is trapped by the glass. The result is heating of the greenhouse above the outside temperature. Source: Botanical Gardens, V.L. Komarov Botanical Institute, obtained from https://en.wikipedia.org/wiki/Greenhouse 13 The Greenhouse Effect: How Greenhouse Gases Work to Keep the Earth Warm The greenhouse effect is the trapping of heat by gases in the earth's atmosphere. • Earth has naturally occurring greenhouse gases. • These naturally occurring greenhouse gases are primarily water vapor, carbon dioxide, plus to a lesser extent, methane, and nitrous oxides. • These greenhouse gases keep Earth warm because: 1. The heat from the sun’s short wave radiation can come in through the atmosphere and a portion of it is re-emitted as longer wave radiation. 2. The long wave infrared radiation (heat) from the ground and plants is trapped by the greenhouse gas and keeps us warm, keeping Earth at temperatures that are comfortable for animal and plant life. 3. Without these greenhouse gases, Earth’s temperature would be about the same as on the Moon, or an average temperature of near 0°F or -18°C. The actual surface temperature is about 14°C or 57°F. 14 Life on Earth depends on energy coming from the sun. About half the light reaching Earth’s atmosphere passes through the air and clouds to the surface, where it is absorbed and then radiated upward in the form of infrared heat. About 90 percent of this heat is then absorbed by the greenhouse gases and radiated back toward the surface, which is warmed to a life-supporting average of 59 degrees Fahrenheit (15 degrees Celsius). Source: Global Climate Change: Vital Signs of the Planet, https://climate.nasa.gov/causes 15 The Greenhouse Effect: Too Much of a Good Thing The increase of Earth’s temperature is primarily due to increasing concentrations of carbon dioxide in the atmosphere. • Earth’s greenhouse gas increases are primarily due to human activities. • Earth’s greenhouse gas concentration was at about 270 parts per million (ppm) prior to the Industrial Revolution in 1850. • Careful measurements of carbon dioxide in the atmosphere began in 1958. • These measurements show the atmospheric carbon dioxide: • Increases every year. • Goes up and down each year, with the decreases in the summer due to growth of vegetation in the northern hemisphere. • There is a decrease in greenhouse gases during the northern hemisphere summer when all the northern hemisphere trees are growing. When they grow, the trees take carbon dioxide out of the atmosphere. This intake of carbon is how the trees get their material to grow. • There is an increase in carbon dioxide every winter when the trees are dormant and industry is releasing carbon dioxide. • Overall, each year there is more increase in carbon dioxide than decrease. • This gradual increase in carbon dioxide causes global warming. • Computer climate models, which replicate the climate’s history, are used to make projections of Earth’s environment in the future. 16 Source: https://www.esrl.noaa.gov/gmd/ccgg/trends/full.html 17 The Greenhouse Effect: Outlook for the Future Climate Models are based on the mathematical equations that represent the laws of Earth’s physics, chemistry and biology. Models can evaluate and isolate the specific causes of climate change and can explore the consequences of different scenarios of future greenhouse gas emissions, aerosol emissions, changes in land use, and other influences on climate. Models can replicate the major events of the industrial age climate, including the gradual warming as greenhouse gases have been emitted, the transient cooling effects of volcanoes, etc. Studying how climate responded to major changes in the past is a major way of checking that we understand how different processes work and that models are capable of performing accurately under a wide range of conditions. Source: https://science2017.globalchange.gov/chapter/executive-summary/ 18 The top panel shows observed and reconstructed mean sea level for the last 2,500 years. The bottom panel shows projected mean sea level for six future scenarios. The six scenarios—spanning a range designed to inform a variety of decision makers—extend from a low scenario, consistent with continuation of the rate of sea level rise over the last quarter century, to an extreme scenario, assuming rapid mass loss from the Antarctic ice sheet.
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